Prior to the events of the game, Vayne killed his two older brothers believing they would betray Archades and their father. With Larsa, on the other hand, Vayne is protective, wanting to keep him from the violence of war.

Vayne is made Consul

When Vayne is first introduced, he has just been appointed the Consul of Rabanastre, effectively making him the Archadian ruler of Dalmasca. Shortly thereafter, however, Vayne is called back to Archades by the Senate, who favor his younger brother Larsa in the position. Vayne, angered by this decision, murders his own father, and seizes the Senate who he blames for the tragedy. He then takes it upon himself to act as the new Emperor. Judge Drace is not fooled by Vayne and accuses him of murder, and Vayne orders her execution to demonstrate his complete power.

Working with Dr. Cid, Vayne works toward a future where the fate of humanity is out of the control of the Occuria and back in the hands of Man. Using the empowered airship Bahamut, Vayne continues to exert his power over Ivalice. When the party boards the airship, a fight ensues with Vayne. When he is defeated, he uses the power of the manufacted nethicite to transform into Vayne Novus. Gabranth, who has been witness thus far, turns on Vayne and strikes him with his sword. Vayne fatally wounds Gabranth with his inhuman strength. While distracted by Larsa, Vaan strikes at Vayne with a mortal wound. Vayne limps outside and Venat lends Vayne its power for all he has accomplished. Vayne then fuses with parts of The Bahamut, transforming himself into The Undying. When he is finally defeated, he explodes into dust.

Vayne is a three-part boss fight, so it's important to remain as healthy as possible between fights. Vayne's attacks are generally single target, but he sometimes uses combos. Use your support character to cast Dispel on Vayne to get rid of Bravery, Haste, and Protect right away. Cast Protect, Shell, Haste, and Bubble on your party members and keep them healed. Use items if you have them (you won't need them after this anyway) and conserve MP for the upcoming battles. Have your front-line fighter in your best armor as always, and you can use Decoy to keep Vayne focused on him/her.